W210 SRS Light & Fault codes

[markjs799]

The SRS light on my 98 E240 has been on since I bought it. The MOT is approaching so I took to a dealer a couple of weeks ago to get the codes read, the following SRS codes were found:

3-032 - AB Control Unit : Terminal 15R has undervoltage or overvoltage
1-000 - Control Unit AB is defective

This doesn't really tell me much, and I haven't been able to find any information on what terminal 15R refers to.

Anyone know anything about these codes?

 

[andy27168]

Hi,
15R = Battery Voltage; Ignition/Starter Switch in "Accy" (pos.1) "Run" (pos.2) or "Start".

Possibly generated by disconnecting a component of the SRS system and switching the ignition on.
Was it a main dealer that read the codes for you? did they try to clear them? then retest?

 

[markjs799]

Hi,
15R = Battery Voltage; Ignition/Starter Switch in "Accy" (pos.1) "Run" (pos.2) or "Start".

Possibly generated by disconnecting a component of the SRS system and switching the ignition on.
Was it a main dealer that read the codes for you? did they try to clear them? then retest?

Thanks for your reply

Yes it was a main dealer, I took it in specifically for them to diagnose this problem but the man I spoke to was a bit vague and seemed more interested in doing a general sort of 'health check' on the car, presenting me with a large quote to fix every issue with the car except the SRS light

First he said something like they weren't allowed to clear the codes until the problem had been rectified, then later he said they tried to clear them but the light just came back on

 

[bob6600]

The readout doesn't look like a STAR machine but I could be wrong.

be careful with airbag modules and connectors. I would switch off, disconnect the battery and check everything. Was the battery low at any point? On reconnection you will need to reset the windows (one touch) and turn steering lock to lock and back to centre to get rid of the BAS ESP errors

 

[markjs799]

The readout doesn't look like a STAR machine but I could be wrong.

be careful with airbag modules and connectors. I would switch off, disconnect the battery and check everything. Was the battery low at any point? On reconnection you will need to reset the windows (one touch) and turn steering lock to lock and back to centre to get rid of the BAS ESP errors

Before I bought it I think the car had been parked up for a while so the battery voltage may have dropped a bit. I put a multimeter on it the other day with the engine not running and battery voltage was 12.4v. The documentation given to me with the car indicates the battery was replaced in late 2014.

After a bit more searching online it seems that the code I have is actually b1000, just formatted differently in the printout from the dealer. From reading this thread it seems that whatever caused it, this code cannot be cleared and the SRS control unit will need replacing.

I've ordered a second hand control unit with an identical part number to the the one in my car, it looks like I might need to get this coded though?

 

[bob6600]

Alex's reply in post #9 is what you want to follow, he is very knowledgeable. My only concern is that it will need coding, not sure if it needs online SCN coding or not though but Alex states some second hand units may not take a new VIN

 

[markjs799]

Just an update on this, the replacement SRS module arrived and I fitted it today. Not done any coding yet, but after reconnecting the battery and turning the ignition on the SRS light now seems to come on and go out as it should.

I'm pretty chuffed considering I only paid £10 for the module

Fingers crossed it stays out. If not, I have an independent locally that can code it if required.